| 摘要 |
PURPOSE: A band pass filter for RF unit is provided to achieve improved attenuation characteristics by forming a notch pole at the low frequency band, while reducing the size of the RF unit and simplifying the structure of the filter. CONSTITUTION: A band pass filter comprises a ground layer(10) having a ground terminal(11); the first resonator layer(20) stacked onto the ground layer, and which has a plurality of ground electrodes(22) arranged along the upper periphery of the first resonator layer, and two resonator circuits(21,21') formed by printing process; the second resonator layer(30) stacked onto the first resonator layer, and which has two resonator circuits(31,31'); the second ground layer(40) stacked onto the second resonator layer, and which has a ground terminal(41); a capacitor layer(50) stacked onto the second ground layer, and which has capacitors(51,51'); and a ground layer(60) stacked onto the capacitor layer.
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